JPH0393007A - Method of manufacturing magnetic head with properly oriented axis of easy magnetization and head manufactured by the same - Google Patents

Abstract

PURPOSE: To orient an axis of easy magnetization in parallel with an air gap by paralleling the axis of easy magnetization of a magnetic head with a spacer in the narrow horizontal direction branch of a U-shaped part. CONSTITUTION: A substrate 30 is provided thereon with a metallic layer 32, the nonmagnetic spacer 40 and a resin layer 42. The resin 42 is masked to form a rectangular pattern on the periphery of the spacer 40 and, thereafter, the resin 42 is irradiated and removed to form grooves. For example, the metallic layer 32 is used as an electrode and while an external magnetic field Hext parallel with a y-axis, i.e., the spacer 40 is applied, a magnetic layer 52 is formed by, for example, electrolyte precipitation. Then, the axis of easy magnetization parallels with Hext (i.e., y-axis) through the entire part of the magnetic patterns. Since the size of the rectangular pattern is large, the occurrence of an edge effect is averted. The residual resin is removed and the magnetic pattern is etched by an etching method in order to obtain the U-shaped magnetic pattern having two magnetic pole pieces PP1, PP2 isolated by an air gap G packed by the spacer 40.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic head having a suitably oriented easy axis of magnetization, and a head manufactured by the method. The invention is used in magnetic recording. Heads manufactured with the method of the invention can be of the write and read type, or of the read or write type.

FIGS. 1 and 2 illustrate embodiments of such narrow recording head read and write magnetic heads.

The magnetic head 10 is disposed on a side surface 12 of a generally catamaran-shaped support 14. The width of the recording medium 16 is approximately 2 μm
It is.

The head essentially consists of two pole pieces PP1, PP2 of limited thickness (e.g. 2 μm) and of e.g. FeNi separated by a very narrow air gap G (e.g. 0.3 μm). It has a magnetic circuit with one part. These pole pieces have two "vertical" branches BVI, 13V2 (generally oriented perpendicular to the plane of the recording medium) and relatively wide (of a few tens of mm); } and with a much narrower "horizontal" branch Bl+ (about 1/10 mm)
It forms a shape pattern. The magnetic head has a second part for re-closing the magnetic flux. In FIG. 2, the second part is in the form of a ferrite rod 20 which is connected at its ends to the pole pieces. The rod is made of copper, for example, and has a diameter of 15
It is wound by a μ-ring conductor coil 22. Such heads can read and write information on media 16. Many other types of heads, such as French Patent Publication No. 2
604 021, or a head with a coil formed from a Film deposited by microelectronic methods, as described in French Patent Publication No. 2 61, for example.
2 876 or European Patent Publication No. 0 269
There are simply read heads with a magnetically sensitive element inserted into a magnetic circuit, as described in US Pat.

There is no need to describe all these variants, since the invention essentially concerns the manufacture of the first part of the magnetic circuit, namely the U-shaped part with two pole pieces and an air gap.
The examples of FIGS. 1 and 2 are suitable for understanding the problem solved by the invention. FIG. 3 outlines the functions performed by such a head. The head is placed in front of a track 16 whose magnetization can be in either of two directions. The magnetic induction of the 16-polar moons PPI and PP2 is represented by arrows.
This guide is closed by a rear part 25 (not shown). The guidance is substantially parallel (
ie parallel to the X-axis) and substantially perpendicular (ie parallel to the y-axis) in the two wide vertical branches IIIVI, BV2.

To reduce noise in the electrical read signal and improve head efficiency, the easy axis of the magnetization (the magnetization obtained in the absence of any external magnetic field) of the magnetic layer forming the pole piece should be In order to take full advantage of the coherent rotation phenomenon, it must be perpendicular to the guidance obtained in the presence of the recording medium.

In the inactive state, i.e. when the recording medium is away from the recording medium, the magnetization has the configuration shown in FIG. The two wide vertical branches BVI, BV2 are ideally generally horizontal (parallel to X).

If known methods for manufacturing such heads, such as those using electrolytic deposition as described in US Pat. No. 4 402 801 or European Patent Publication No. 0 262 028, are applied without particular care , you can never get a contemplative situation like this. It is also possible to obtain the opposite situation as shown in FIG. FIG. 5 shows several stages in the manufacture of such a head.

The following operations are carried out in a known manner.

Metal M32 and then resin 34 are deposited on nonconductive substrate 30 (a). (If the substrate is a conductor or semiconductor, no metal layer is needed.) The resin is irradiated and developed to obtain steps 36 (b). after that. For example, PA is silica non-magnetic (amaHnetic).
) A layer of material 38 is deposited<c).

The horizontal portions of N36 and 38 are removed by reactive ion etching to leave only the non-magnetic wall 40 (d)
.

The whole is coated with resin 42 (e).

Grooves 44, which are shaped like a U-shaped pattern and are to form later pole pieces, are etched in the resin (f in plan view, g in cross-section through wall 40).

In the presence of an external magnetic field 11ext, an electrolytic deposit 46 made of, for example, FeNi is shaped into the groove (h).

The residual resin is removed and the two pole pieces PPI, PP2
A U-shaped circuit with a non-magnetic spacer 40 in the air gap G is obtained (i.j). NEXT is oriented parallel to wall 40 to try to obtain an easy axis parallel to the air gap.

The axis of easy magnetization is Hext in the vertical branch of the U-shaped circuit.
Due to the very pronounced edge effect that causes anisotropy in the parallel but narrow horizontal, directional branch, the magnetic easy axis is turned to become parallel to the horizontal edge.

Therefore, the obtained result (1) is contrary to the desired result (FIG. 4).

Turning or tilting the external magnetic field}1ext by about 90° actually gives the desired orientation in the wide branches, but around the air gap the orientation is still impaired.
However, it is in this narrow area that the magnetic phenomena are strongest and require proper orientation of the easy axis.

The aim of the invention is to rectify this drawback. To this end, the invention provides a narrow horizontal branch and a method by which an orientation of the magnetic easy axis on both sides of the air gap, not parallel to the air gap, but in other words parallel to the spacer or y-axis, can be realized.

As an advantageous variant, the invention may provide an orientation of the easy axis perpendicular to said direction (ie perpendicular to the air gap, spacer or y-axis) in two wide vertical branches.

This objective is achieved because a large magnetic pattern is formed that avoids the edge effect phenomenon. Then, once the magnetization is properly oriented, the pattern is given the required dimensions.

The present invention relates, inter alia, to a method comprising essentially the following operations.

First non-magnetic spacers are formed on the substrate.

The spacer has a thickness equal to the rear air gap and a certain general direction.

Then, in order to construct a pattern with much larger dimensions in the area of the spacer than the later narrow horizontal branches,
A magnetic layer is deposited around the spacer. During this work,
A magnetic field is applied whose direction is parallel to the direction of the spacers, and the magnetic layer thus obtained has an easy axis of magnetization parallel to the spacers in the pattern.

To keep only the desired narrow horizontal branches,
Excess portions of the layer within the area of the spacer are removed.
At that point the branch has an easy axis parallel to the spacer.

Two variants of this inventive method are provided.

In a first example, a substantially rectangular magnetic pattern is formed around the spacer. The pattern is then etched to leave only the desired U-shaped circuit with a narrow horizontal branch and two wide vertical branches. The resulting whole part is then cut in a conventional direction and polished.

In a second example, a pattern is formed with two vertical branches that already have a final shape and a horizontal branch that is much wider than the desired final horizontal branch. to remove the extra lower portion of the horizontal branch to give it its final width;
The entire section is cut and ground perpendicular to the spacer.

To achieve the required ideal orientation within the horizontal branch and the two vertical branches, the direction of the spacer is perpendicular to the The method can be continued with a complementary magnetic layer deposited on the perpendicular branches in the presence of a oriented magnetic field.

In all these embodiments, the deposition of the magnetic layer may be performed by electrolytic deposition. However, any other known method can be used, such as cathodic sputtering. The invention further relates to a magnetic head obtained by the method described above. The magnetic head is characterized by a narrow horizontal branch of the U-shaped section with the easy axis of magnetization parallel to the spacer. In an advantageous variant, the two wide vertical branches have in each case an overthickness section with an easy axis of magnetization perpendicular to the spacer.

BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting embodiments of the invention will now be described in more detail with reference to the accompanying drawings.

The method of the present invention applies the first operation of the method shown in FIG. 5, particularly the operations at stages a to e in the drawing. FIG. 6 shows the continuation of the work to be carried out from the component shown in part a.

This component includes a substrate 30, a metal layer 32, a non-magnetic spacer 40, and a resin layer 42 (ie, FIG. 6a is the same as FIG. 5e[g). The method of the invention continues with the following operations.

The resin is masked to form a substantially rectangular pattern around the spacer. The resin is then irradiated and removed to form the grooves (top view b, cross-section C).

For example, the magnetic layer 52 is formed by electrolytic deposition, for example, using the metal layer 32 as an electrode and applying an external magnetic field tlext parallel to the y-axis, ie parallel to the spacer (d, e). Therefore, the easy axis of magnetization is parallel to IText (i.e., the y-axis) throughout the magnetic pattern, and the occurrence of edge effects is avoided due to the large dimensions of the rectangular pattern. The residual resin is removed and filled with spacers 40. Two pole pieces P separated by an air gap G
The magnetic pattern is etched by a conventional etching method to provide a U-shaped magnetic pattern comprising PI, PP2 (f). Even during etching, the easy axis of magnetization retains its orientation and is thus finally oriented properly, ie parallel to the air gap or spacer.

In a second variant of the invention, the formed magnetic pattern already has two vertical U-shaped branches, so that the already formed vertical branches 61 . 62 and a horizontal portion 63 that is much wider than the later horizontal branch 8H is formed in resin 42 in FIG. 7(a). A magnetic layer 64 is formed in the groove (b), for example by electrolytic deposition, in the presence of a magnetic field It e X t directed according to the y-axis. The resulting part is then cut and polished to remove the lower part 65 until the desired width for the horizontal part 66 is obtained (c).

During these cutting and polishing operations, the axis of easy magnetization is I{
remains parallel to the direction imposed by e x t, ie parallel to the spacer 40.

Although the method described above solves the problem of establishing an easy axis of magnetization around the air gap parallel to the air gap, which is important, the head is still incomplete. This is because in the vertical branch of the U-shaped circuit, the easy axis of magnetization does not have the desired orientation (the fourth
(see figure). Although secondary, this problem can be solved by the present invention by continuing the method by the operations shown in FIG.

The component obtained as described above (depending on whichever variant of FIG. 6 or FIG. 7) is obtained is coated with resin 70. Vertical branch BVI of the already formed pole piece
, the resin is irradiated through a mask, then developed and removed (a>. e.g. in the presence of an external magnetic field H' ext parallel to the A magnetic layer is formed on these two layers by electrolysis growth (b), and then the resin is removed. This results in an excess thickness 76.78 (b, c), where the excess The axis of easy magnetization within the thickened section is parallel to the X-axis and perpendicular to the magnetic flux which then passes in a favorable manner into the overthickened section. These zones further reduce the reluctance of the magnetic circuit. , thereby improving the efficiency of the head without compromising the thin part of the pole piece in the air gap area.Therefore, the head obtained (8th
Figure, part C) has easy axes of magnetization oriented in two directions. That is, the axis is parallel to the y-axis near the air gap,
For wide branches, it is parallel to the X axis. This constitutes the desired ideal head9.

[Brief explanation of drawings]

Figure 1 shows the magnetic head on the catamaran pad, Figure 2
Figure 3 shows the arrangement of ferrite rods with coils.
4 shows the ideal orientation of the easy axis of magnetization; FIG. 5 shows the various stages of the manufacturing method of the head according to the prior art; FIG. 6 7 is a diagram showing the main steps of the method of the invention, FIG. 7 is a diagram showing a modification of the method of the invention, and FIG. 8 is a diagram showing various stages of implementation of the improved method of the invention. 10. ．． ．． magnetic head, 30. ．． ．． Substrate, 32. ．． ．． Metal layer, 34, 42, 70. ．． ．． resin layer, 40. ．． ．． Spacer, 44,60.72,74. ．． ．． Groove, 52, 84.
．． ．． Magnetic layer, 76.78. ．． ．． Excessive thickness. Kofu L Kamiichi

Claims (7)

[Claims] (1) A method of manufacturing a magnetic read and/or write head, comprising: a U-shaped first pole piece consisting of two wide vertical branches and a narrow horizontal branch separated by an air gap; and a second magnetic flux closure portion connecting the two vertical branches of the U-shaped portion, the circuit comprising means for detecting and/or generating magnetic flux fluctuations. , U
To obtain a shaped part, first a non-magnetic spacer is formed on the substrate with a thickness equal to the later air gap and a predetermined general direction, and then a dimension much larger than the later narrow horizontal branch. a magnetic layer is deposited around the spacer to form a pattern having in the area of the spacer;
During this operation an external magnetic field with a direction parallel to the direction of the spacers is applied, so that the magnetic layer thus obtained has an easy axis of magnetization parallel to the spacers in the pattern and the desired narrow horizontal branches. A method characterized in that an extra part of the layer is removed in the area of the spacer in order to retain only the branch, at which point the branch has an easy axis of magnetization parallel to the spacer. (2) A substantially rectangular magnetic pattern is formed around the spacer such that the pattern then leaves behind only the desired U-shaped circuit comprising a narrow horizontal branch and two wide vertical branches. 2. A method according to claim 1, characterized in that the etching is carried out by etching. (3) A pattern is formed with two vertical branches that already have a U-shaped final shape and a horizontal branch that is much wider than the desired final horizontal branch; In order to remove the excess lower part and give the horizontal branch a final width,
2. A method as claimed in claim 1, characterized in that the entire section is cut and ground at right angles to the spacer. (4) After manufacturing the U-shaped magnetic circuit, in the presence of an external magnetic field with a direction perpendicular to the direction of the spacer, in order to obtain two excess thickness parts with easy magnetization axes perpendicular to the direction of the spacer. 4. A method according to claim 2 or 3, characterized in that a complementary magnetic layer is deposited on parts of the vertical branches. (5) A method according to any one of claims 1 to 4, characterized in that the magnetic layer is formed by electrolytic growth of a magnetic material. (6) A magnetic read and/or write head manufactured by the method of claim 1, wherein the head comprises:
a first U-shaped section comprising two wide vertical branches and a narrow horizontal branch separated by an air gap filled by a non-magnetic spacer, and a second U-shaped section connecting the two vertical branches of the U-shaped section. a magnetic circuit incorporating a magnetic flux closure portion of the magnetic flux, the circuit comprising means for detecting and/or generating magnetic flux fluctuations, the magnetic layer having an easy axis of magnetization parallel to the spacer in a narrow horizontal branch; A head characterized by: (7) Magnetic reading and/or writing according to claim 6, characterized in that the two wide vertical branches further have in each case an excess thickness section with an easy axis of magnetization perpendicular to the spacer. head.